Golf club head

ABSTRACT

A golf club head comprises a metallic basal body and a multilayer coating thereon, the multilayer coating comprises a foundation coat of a priming paint, a color coat of a coloring paint, an iridescent coat of an iridescent paint and a clear coat of a transparent and colorless paint, the iridescent paint contains a resin, a colorant and an iridescent material, the iridescent material is at least one kind of flakes selected from the group consisting of colored aluminum flakes, metal flakes whose surface is resin-treated, mica flakes coated with a titanium oxide, and flakes of mica itself, the iridescent coat has a thickness of from 10 to 40 microns, and the overall thickness of the multilayer coating is not more than 100 microns.

BACKGROUND OF THE INVENTION

[0001] The present invention relates to a golf club head more particularly to a multilayer coat capable of improving the appearance.

[0002] In the golf club heads, there are demands for beauty and high-quality impression in the appearance as well as demands for performance such as carry, directional controllability and like. In the wood-shaped golf club heads, as the size is large and round, the demands concerning the appearance especially color are strong in comparison with other types of heads.

[0003] In recent years, therefore, golf club heads having a coating of metallic pigmented paint or so called pearl paint containing ground mica have been proposed. The metallic pigmented paint or pearl paint is, as shown in FIG. 3, applied to the surface of a transparent and colorless priming paint (b) on the basal body (a) of the head and covered with a clear coat (d), whereby a triple-layer coating (e) is formed.

[0004] In such a triple-layer coating, however, it is difficult to achieve a jewel-like iridescent deep-color.

SUMMARY OF THE INVENTION

[0005] An object of the present invention is therefore to provide a golf club head which is iridescent and will be appreciated by many golfers as being more beautiful and high-quality than those of the pearl paint coating or metallic pigmented paint coating.

[0006] According to the present invention, a golf club head comprises a metallic basal body and a multilayer coating thereon, the multilayer coating comprising a foundation coat of a priming paint, a color coat of a coloring paint, an iridescent coat of an iridescent paint and a clear coat of a transparent and colorless paint which coats are arranged in this order from the inside to the outside,

[0007] the iridescent paint containing a resin, a colorant and an iridescent material, the iridescent material being at least one kind of flakes selected from the group consisting of colored aluminum flakes, metal flakes whose surface is resin-treated, mica flakes coated with a titanium oxide, and flakes of mica itself,

[0008] the iridescent coat having a thickness of from 10 to 40 microns, and

[0009] the overall thickness of the multilayer coating being not more than 100 microns.

[0010] Preferably, colored aluminum flakes are used as the iridescent material.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011]FIG. 1 is a perspective view of a golf club head according to the present invention.

[0012]FIG. 2 is an enlarged cross sectional view of the coating thereof.

[0013]FIG. 3 is an enlarged cross sectional view of the conventional pearl paint coating.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0014] An embodiment of the present invention will now be described in detail in conjunction with the accompanying drawings.

[0015] In this embodiment, golf club head 1 according to the present invention is a wood-shaped head comprising a metallic basal body, the surface of which excepting the sole is covered with a multilayer coating 3. Incidentally, the coating area can be determined according to the need.

[0016] The basal body 2 is made by assembling a plurality of parts made by casting, forging, pressing and the like of at least one kind of metallic material. In this embodiment, a titanium alloy is used in the parts because the strength-to-weight ratio is high. But, it is also possible to use other metallic materials.

[0017] Firstly, a priming paint is applied to the surface of the basal body 2 after the surface is polished by means of wire brush, sand blasting or the like. If the surface has pinholes or the like, they are stopped up with putty.

[0018] The priming paint is a transparent and colorless heat-hardening paint which contains a solvent, a synthetic resin such as polyester, polyurethane, epoxy, acrylic resin and the like as its base. In this embodiment, a polyester resin enamel is used because of a high impact strength and strong adhesion to metallic materials such as titanium alloy, stainless and the like.

[0019] In order to harden, the applied priming paint is baked, for example at about 150 deg. C. for about 15 minutes, whereby a hard foundation coat 3 a is made.

[0020] The foundation coat 3 a preferably has a thickness in a range of from 5 to 40 microns, more preferably 10 to 25 microns. The foundation coat 3 a can improve the adhesion to the under-mentioned overcoat. If the thickness is less than 5 microns, it is difficult to even the microscopic roughness of the surface. If more than 40 microns, there is a tendency for the adhesion and impact resistance to decrease.

[0021] Next, a coloring paint is applied to the surface of the foundation coat 3 a.

[0022] The coloring paint is a liquid heat-hardening paint containing a solvent, a pigment and a synthetic resin such as polyester, polyurethane, epoxy, acrylic resin and the like as its base.

[0023] In connection with the color of the coloring paint, it is preferable that reflection from the foundation coat 3 a is shut out. Therefore, a dark color such as black or blackish color is preferably used. In this example, a black color is employed although the key color of the finished head is a dark green. of course, the key color of the head can be another color. Accordingly, a black pigment is used, and in this example, acrylic resin is used as the base resin.

[0024] In order to harden, the applied coloring paint is baked, for example at about 150 deg. C. for about 15 minutes, whereby a hard color coat 3 b is formed on the foundation coat 3 a. If the color coat 3 b is too thin, it is difficult to obtain the under-mentioned iridescent effect. If too thick, the color coat becomes brittle. Therefore, it is preferable that the thickness of the color coat 3 b is set in a range of from 1 to 25 microns, more preferably 5 to 15 microns.

[0025] Thirdly, an iridescent paint is applied to the surface of the color coat 3 b.

[0026] The iridescent paint is a liquid heat-hardening paint which contains a solvent, a colorant, an iridescent material 4 and a transparent synthetic resin such as polyester, polyurethane, epoxy, acrylic resin and the like as its base.

[0027] When the above-mentioned color coat 3 b is black or blackish, the key color of the finished head is determined almost solely by the color of the iridescent paint. If the color coat 3 b has a light color, the reflection therefrom blurs the reflection by the iridescent paint. From a point of view of this fact too, it is preferable that the above-mentioned color coat 3 b is black or blackish.

[0028] As the iridescent material, colored specular aluminum flakes, specular metal flakes whose surface is resin-treated, mica flakes coated with a titanium oxide, flakes of mica itself can be used. Here, the colored aluminum flakes means aluminum flakes colored by vapor deposition.

[0029] It is not always necessary that the iridescent material itself is iridescent as far as the coat as a whole is iridescent. In case of material itself being iridescent, a chromatic polarizing material can be used.

[0030] In this embodiment, an acrylic resin is used as the base resin, and colored aluminum flakes are used as the iridescent material. The colorant in this example is a green pigment. It is however possible to use a dye or a soluble substance in this invention.

[0031] The colored aluminum flakes are preferable because it is easy to select a color and obtain the same color and a higher reflectance in comparison with other materials.

[0032] The average size of the above-mentioned colored aluminum flakes is set in a range of from about 10 to about 100 microns, wherein the size of a flake is defined as a maximum size in the normal direction to the thickness direction of the flake.

[0033] Given that the total weight of the resin, pigment and iridescent material (excluding the solvent) is 100, the content in weight % of the pigment is set in a range of from 0.1 to 5.0, preferably 0.2 to 4.0, more preferably 2.0 to 4.0, and the content in weight % of the iridescent material is set in a range of from 0.1 to 7.5, preferably 0.5 to 5.5.

[0034] The flakes of the iridescent material may be dispersed randomly (not oriented), but it is preferable to orient in a specific direction.

[0035] The flakes can be oriented such that the flakes becomes generally in parallel with the surface of the coating. This orientation may be preferably employed when the material itself is iridescent such as a chromatic polarizing material. In this case, in order to enhance the iridescent effect, relatively large flakes are preferably used, and further, as the colorant, a light-color pigment or a dye is used not to hide the iridescent effect.

[0036] Further, the flakes can be oriented such that the flakes becomes generally normal to the surface of the coating, in other words, the thickness directions of the flakes become generally in parallel with the surface of the coating. In this case, when the coating is viewed oppositely or normally thereto, the color is mainly determined by that of the colorant, but when viewed obliquely, as the percentage of the color of the iridescent material increases, the color as a whole changes. This orientation may be preferably employed when the material itself is not iridescent.

[0037] In any case, a color change also occurs by change in the incident light (direction and intensity) in addition to the change in the direction of view.

[0038] In order to harden, the applied iridescent paint is baked, for example at about 150 deg. C. for about 10 minutes, whereby a hard iridescent coat 3 c is formed on the color coat 3 b. The thickness of the iridescent coat 3 c is set in a range of from 10 to 40 microns, preferably 15 to 35 microns.

[0039] Fourthly, a clear paint is applied to the surface of the iridescent coat 3 c in order to protect the iridescent coat 3 c and improve the durability and impact resistance of the coating.

[0040] The clear paint is a transparent and colorless heat-hardening paint which contains a synthetic resin such as polyester, polyurethane, epoxy, acrylic resin and the like as its base. In this example, a polyester resin is used as the base resin.

[0041] The applied clear paint is baked at about 150 deg. C. for about 15 minutes, whereby a hard clear coat 3 d is formed on the iridescent coat 3 c.

[0042] The overall thickness (t) of the coating 3 is set in a range of not more than 100 microns, preferably 25 to 90 microns, more preferably 40 to 80 microns.

[0043] If the overall thickness is more than 100 microns, the impact resistance is liable to decrease.

[0044] If the thickness of the iridescent coat 3 c is less than 10 microns, it is difficult to obtain a beautiful color depth. If more than 40 microns, the coat becomes brittle and the impact resistance tends to decrease.

[0045] If the iridescent material is too much, the head becomes glaring and there is a possibility that the golfer is disturbed. If the iridescent material is insufficient, effective iridescent effect can not be obtained. If the pigment is too much, the iridescent material is masked, the iridescent effect can not be obtained. If the pigment is insufficient, it is difficult to achieve the key color.

Comparison Tests

[0046] Changing the thicknesses of the coats, golf club heads were prepared and tested for the impact resistance and appearance.

[0047] In the impact resistance test, an iron rod of 500 grams was dropped to the coating of the head from a position 150 mm above the head. Based on the size and depth of the damaged part, the impact resistance was evaluated into five ranks, wherein the larger the rank number, the higher the impact resistance.

[0048] At to the appearance, the depth of color, and color change were evaluated into five ranks.

[0049] The specifications and test results are shown in Table 1.

[0050] Form the test results, it was confirmed that, according to the present invention, the color of the golf club head changes from navy blue under indoors' soft light to brilliant metallic green under outdoors' strong light, and a beautiful head can be obtained without sacrificing the impact resistance. TABLE 1 Head Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5 Ex. 6 Ex. 7 Ex. 8 Ex. 9 Ex. 10 Ref. 1 Ref. 2 Ref. 3 Ref. 4 Number of coats 4 4 4 4 4 4 4 4 4 4 3 4 4 4 Foundation coat Thickness (micron) 10 15 15 15 10 10 10 10 10 10 10 10 10 20 Color coat Thickness (micron) 5 15 15 10 10 5 5 5 5 5 0 10 5 15 Color blk. blk. blk. blk. blk. blk. blk. blk. blk. blk. — blk. blk. blk. Iridescent coat Thickness (micron) 25 10 15 35 40 10 15 35 40 25 25 5 50 35 Colored aluminum flakes Weight % 4 4 4 4 4 4 4 4 4 4 10 4 4 4 Pigment Weight % 2 2 2 2 2 2 2 2 2 4 2 2 2 2 Color green green green green green green green green green green green green green green Clear coat Thickness (micron) 20 50 45 30 30 25 25 25 25 20 20 35 25 50 Overall thickness (micron) 65 90 90 90 90 50 55 75 80 65 55 60 90 120 Impact resistance 5 4 4 4 3 5 5 4 3 5 5 5 2 1 Depth of color 5 3 5 5 4 3 5 5 4 5 1 1 5 5 Color change 5 3 4 5 5 3 4 5 5 5 3 1 5 5 

1. A golf club head comprising a metallic basal body and a multilayer coating thereon, said multilayer coating comprising a foundation coat of a priming paint, a color coat of a coloring paint, an iridescent coat of an iridescent paint and a clear coat of a transparent and colorless paint which coats are arranged in this order from the inside to the outside, the iridescent paint containing a resin, a colorant and an iridescent material, said iridescent material being at least one kind of flakes selected from the group consisting of colored aluminum flakes, metal flakes whose surface is resin-treated, mica flakes coated with a titanium oxide, and flakes of mica itself, the iridescent coat having a thickness of from 10 to 40 microns, and the overall thickness of the multilayer coating being not more than 100 microns.
 2. A golf club head according to claim 1, wherein the iridescent material is the colored aluminum flakes.
 3. A golf club head according to claim 1 or 2, wherein the flakes of the iridescent material are generally oriented in a certain direction with respect to the surface of the head.
 4. A golf club head according to claim 1 or 2, wherein the flakes of the iridescent material are generally oriented in a direction parallel to the surface of the head.
 5. A golf club head according to claim 1 or 2, wherein the flakes of the iridescent material are generally oriented in a direction normal to the surface of the head.
 6. A golf club head according to claim 1, wherein said color coat has a black color or a blackish color darker than the colorant of the iridescent paint.
 7. A golf club head according to claim 1, wherein the colorant of the iridescent paint is a pigment whose content in weight % is in a range of from 0.1 to 5.0 with respect to the total weight of the pigment, the resin, and the iridescent material which is
 100. 8. A golf club head according to claim 7, wherein the content in weight % of the iridescent material is in a range of from 0.1 to 7.5 with respect to said total weight of the pigment, the resin, and the iridescent material. 